Recent content by lukasch

I would explain it in this way - for a system of noninteracting fermions with hamiltonian ham = sum_k c^+_k_up c_k_up + c^+-_k_down c^-_k_down you can apply the fermi-dirac statistic, which says that a one-electron state |i> is occupied with probability < c^+_i c_i > = f(Ei) = 1/(1+exp(...

Hi there, I would appreciate if you could share your exeriences or ideas about properties of 4x4 symmetric/hermitean matrices H such that U^T H U = D = diag( E1, -E1, E2, -E2 ) or diag (E1, E2, -E1, -E2 ) The things I would like to perform are the following - decompose an expression...